On Wed, Apr 12, 2017 at 02:27:44PM -0400, Steven Rostedt wrote: > + * schedule_idle() is similar to schedule_preempt_disable() except > + * that it never enables preemption.
That's not right. The primary distinction is that it doesn't call sched_submit_work(). And because that function is a no-op for the idle thread, the idle thread can do without calling that and therefore avoid the preemption window. You also need a few words about fake idle threads, search play_idle() callers. You could also make schedule_idle() more robust by adding a WARN for the blk_schedule_flush_plug() condition. You Changelog is still entirely long and rambling but fails to mention the fundamental important stuff :-(
